Implement Phase 1 tasks 1.1-1.4 (scaffold + core types + config + Postgres)

Scaffold mirrors tcp-ingestion conventions: ESM, strict TS, pnpm, vitest
with unit/integration split, ESLint flat config with no-floating-promises
+ no-misused-promises + import/no-restricted-paths (the new src/core/ →
src/domain/ boundary that protects Phase 1 from Phase 2 churn).

Core types in src/core/types.ts (Position, StreamRecord, DeviceState,
Metrics, AttributeValue) — Position is byte-equivalent to tcp-ingestion's
output. Codec in src/core/codec.ts implements sentinel reversal:
{__bigint:"..."} → bigint, {__buffer_b64:"..."} → Buffer, ISO timestamp
string → Date. CodecError surfaces malformed payload reasons with the
failing field named.

Config in src/config/load.ts (zod schema, all 13 env vars with defaults
and bounded numerics). Logger in src/observability/logger.ts matches
tcp-ingestion exactly: ISO timestamps, string level labels, pino-pretty
in development.

Postgres in src/db/: createPool with sane defaults and application_name,
connectWithRetry mirroring the ioredis retry pattern, a 30-line
migration runner using a schema_migrations table, and 0001_positions.sql
with the hypertable + (device_id, ts) unique index + ts DESC index.
Migration runner unit-tested against a mocked pg.Pool; the real
TimescaleDB round-trip is deferred to task 1.10 per spec.

Verification: typecheck, lint, build all clean; 73 unit tests passing
across 4 files. import/no-restricted-paths verified live by temporarily
adding a forbidden src/domain/ import.

.planning/phase-1-throughput/04-postgres-schema.md

@@ -1,7 +1,7 @@
 # Task 1.4 — Postgres connection & `positions` hypertable
 
 **Phase:** 1 — Throughput pipeline
-**Status:** ⬜ Not started
+**Status:** 🟩 Done
 **Depends on:** 1.1, 1.3
 **Wiki refs:** `docs/wiki/entities/postgres-timescaledb.md`
 
@@ -86,4 +86,4 @@ Do **not** introduce a heavy framework (Knex, node-pg-migrate). The Processor ha
 
 ## Done
 
-(Fill in once complete: commit SHA, brief notes.)
+*(pending commit SHA)* — Implemented `src/db/pool.ts` (createPool, connectWithRetry), `src/db/migrate.ts` (runMigrations — 30-line runner), and `src/db/migrations/0001_positions.sql` (hypertable + unique index + ts-desc index). Unit tests use a mocked pg.Pool throughout; the real TimescaleDB round-trip is deferred to task 1.10 per spec. The "calls process.exit(1)" pool test uses `maxAttempts=1` to avoid fake-timer unhandled-rejection noise that surfaces when a backoff setTimeout resolves after the outer promise has already thrown.